Composition of metal.



'ROBERT C. TOTTEN, OF PITTSBURG, PENNSYLVANIA.

COMPOSITION OF METAL.

Specification of Letters Patent.

Patented Dec. 3, 1907.

e Application filed December 22. 1906. Serial No. 349.169.

. of the same and the articles produced there- .from, its object being to provide from what are known as coke or coal irons, thatis, pig metal smelted with coke or anthracite coal, what is known as a chilling cast iron, that is, a metal suitable for the manufacture of castings of great strength and fineness of grain, such as chilled castings, which have heretofore been made principally from what is known as charcoal iron, the same character of iron being also adapted for the making of malleable castings and for some other uses requiring special strength. Charcoal pig metal has generally been considered a necessity for the manufacture of such chilled castings, the generally understood reason for this being that it is the only pig metal that contains what istermed combined carbon in sufficient uantity to impart to the iron containing it t 10 peculiarity of making a chilled surface when cast against a metal chill. One theory in regard to this combined carbon is that the carbon is chemically united or combined with the iron as distinguished from being. present in graphitic form. ,Wllile thedemand for this charcoal pig iron has been constantly increasing the production of the same has apparently reached its limit, largely on account of the cost of the charcoal necessary for smelting the same.

By my invention I am able to produce from pig iron made by the coke or coal process a chilling cast metalhaving practically the same properties as found in the charcoal pig iron and thus to utilize a cheaper pig iron for the purpose and one of which there is abundant supply.

v.My invention consists, generally stated, in a new composition of chilling cast metalfconsisting of coke or coal iron and a chromium compound containing combined iron and carbon, such as ferro chrome; the ferro-chrome containing a large proportion of such combined iron and carbon and providing in the chilling cast iron so formed a sufficient proportion of combined carbon to give to that metal the peculiar qualities ordinarily found in charcoal iron as above referred to, while the, chrome present adds to the hardness without reducing the strength of the casting so produced. In the manufacture of this chilling cast iron I melt the coke or coal iron in any suitable way, preferably in an air furnace, and I also pre fer to melt the ferro-chrome. I may either melt the iron in one furnace, and melt the ferro-chrome in another furnace or crucible, and add it to the iron, regulating it as found desirable to produce the proper depth of "chill which may be tested while the metal is still molten; or I may add the ferro chrome in solid state to the molten iron in the furnace, or I may add the molten or solid ferrochrome in the ladle which receives the iron from the melting furnace; in this way uniting the two metals or alloysin any suitable or effective way.

The ordinary coke or coal pig iron contains a large amount of graphitic carbon and a small proportion, sometimes only a trace, of combined carbon. Ferro-chrome contains a large proportion of combined carbon ranging as high as ten (10) to twelve (12) per cent. These metals I mix in suitable proportions in order to obtain the requisite amount of combined carbon in the resultant casting iron, it being desired that this proportion shall be as much as one quarter of one per cent. (4; of

1%) of combined carbon for strong, fine grained castings, and as much as one (1) per cent. or over for chilled rolls, car wheels, etc.

For this purpose I can vary the amount of ferro-chrome in any desired proportion, be-

ing melted together or melted separately and I ten (10) per cent. combined carbon, a miX-.

ture would be producedby using twenty to twenty-five per cent (20 to 25%) of such ferro-chrome containing two (2) to two and one half (2% )Hper cent. ,combined carbon, producing a big chilling iron. Or by using the same grade of pig ironand using twenty (20) to twenty-five (25) per-.centxof ferrochromeeontainmg six (6) per cent. combined 2 eve aee carbon, a chilling iron Would be produced of moderate chilling properties. I have found that in this Way I am enabled to produce a casting iron of finegrainand great strength adapted to'produoe castings of the character referred to and cspeciallycl'iilled rolls, oar wheels, etc, with a hard Wearing surface and the necessary strength back of the chilled v surface in the body of the roll or car wheel. It may also be employed to advantage for malleable castings, cylinders and the like requiring special strength.

As the supply ofcharcoal iron is limited, and the supply of ordinary coke or coal iron is practically unlimited I am thus enabled to produce a cheap and suitable substitute for the ordinary charcoal iron, and one which produces a harder and more durable Wearing surface,

What I claim is:

1. A new composition of chilling cast iron, consisting of coke or coal iron and a chromium compound containing combined iron and carbon.

2. A new, composition of chilling cast iron, consisting of coke or'coal iron and ferrochrome.

3. A new com osition of chilling cast iron, consisting of-co e or coal iron and a chro- K 1niu1n compound containing combined iron I and carbon, the composition containing at y least one-fourth (i) of one (1) per cent. of I combined carbon. i

' 4. A new composition of chilling cast iron,

consisting of coke or coal iron and ferro chrome containing at least one fourth (1}) of one (1) per cent. of combined carbon.

C. TOTTEN have hereunto set my hand.

' ROBERT o. TOTTEN;

Witnesses:

M. V. KIEHL, H. M. ConWIN.

In testimony whereof, I. the said 'ROBERTY 

